1. Field of the Invention
The present invention relates to a method for determining the representative color of a metallic paint whose color varies with the angle of observation, a method for classifying and arranging metallic paint colors, and a computer graphic apparatus.
The invention further relates to a computer graphic apparatus for calculating the representative one of metallic paint colors as a hue-tone value, arranging computer graphics of metallic colors expressing their textures on a hue-tone chart, and thereby displaying a chromatological classification of colors and their textures at the same time.
The invention, since it permits identification of the representative color of a paint which contains various effective pigments such as aluminum flakes, mica flakes and plate iron oxide in the coat and whose color varies with the angle of observation, makes possible classification and arrangement of colors and computerized search of colors. Furthermore, the invention provides a computer-based design tool capable of simultaneously evaluating color and texture by superposing computer graphics accompanied with textures.
2. Description of the Prior Art
The colors of the body coating of automobiles in recent years are characterized by the dominance of metallic paints containing various effective pigments (including aluminum flakes, mica flakes and graphite). A metallic paint varies in color with the angle of observation, gives metallic luster, pearly luster or bicolor appearance (an effect to exhibit two or more colors depending on the angle), and this feature is known as texture. As techniques of chromatological classification of the body colors of automobiles, the Munsell scale-and the hue-tone scale have been extensively used for many years.
Solid coating colors can be classified according to a system of color chips prepared with solid pigments. However, it is difficult to extract the representative one out of various colors which a metallic paint would manifest with changes in the angle of observation. Reported methods for classification of others than solid colors including ones for classifying angle-dependent colors for the purpose of grading pearls (Japanese Laid-open [KOKAI] Patent Publication No. 061635/81 and Japanese Laid-open [KOKAI] Patent Publication No. 230778/86), but none of these methods is applicable to so diverse colors as those of automobile body coating.
For this reason, the conventional practice is for the designer to look at metallic paint colors one by one against light, observe color variation from highlight to shade by the eye and, after imaging the representative one of the various colors in his or her head, to finally determine the hue-tone value. This method, however, involves the disadvantages of taking too long a time and variance in results with the designer who appraises the color.
Furthermore, when the designer searches for a color he or she images out of a tremendous variety of paint colors prepared in the past, as the search takes so many man-hours per color checked as the above-described procedure requires, the designer has no other alternative than to make a rough guess to pick out the color he or she remembers, and accordingly is substantially deterred from retrieving the true color.
To sum up the problems noted above, the biggest point is how to determine the representative color of a metallic paint whose color varies with the angle of observation. In a calorimetric approach, if an answer can be given to the question of the calorimetric value taken in what angle can give the representative value of that coating color, the value of that color can be figured out in terms of HVC in the Munsell color scale or the commercial available hue-tone scale, and a color whose value coincides with this calculated value can be chosen as being approximately the imaged color.